The Pies led by just three points at three-quarter time but kicked the first three goals of the final term to score a 9.15 (69) to 9.5 (59) win in front of 72,504 fans.

Jordan De Goey played a huge role in the win, terrorising the Giants defenders all night to kick three goals and have a hand in a few more.

Steele Sidebottom (31 possessions), Scott Pendlebury (25 disposals and 11 tackles) and Adam Treloar (29) did the heavy lifting through the middle and veteran defender Tyson Goldsack continued his remarkable comeback from a knee reconstruction to help keep GWS gun Jeremy Cameron to one goal.

Collingwood looked set for a leisurely hit-out on their way to a prelim with the listless Giants in disarray early.

The rampant Pies kicked the first three goals of the match to lead a goalless GWS by 22 points at the first break, with their inaccuracy the only black mark against them.

Rory Lobb rises high.Source:AAP

But a Stephen Coniglio-led resurgence tipped the game on its head in the second quarter.

Buckley’s men suddenly found themselves under pressure at every turn and they didn’t handle it well.

Ryan Griffen dribbled through the Giants’ first goal of the evening and the visitors added another three majors to the dismay of the overwhelmingly pro-Collingwood crowd.

De Goey’s running shot the split the middle as the halftime siren sounded for the Pies’ only goal of the quarter with tensions boiling over in an all-in melee.

GWS trailed by seven points after the restart but hit the front for the first time with successive goals, including a brilliant set shot from Coniglio on the boundary line.

But Collingwood were able to regroup late in the quarter.

With the crowd at fever pitch, a sublime De Goey gather and give set up Travis Varcoe for the first goal of the final term.

Then Will Hoskin-Elliott rocked his former team with his second major and De Goey goaled from a free kick to set the Pies well on their way to a date with the reigning premiers.

Coniglio was outstanding for the Giants with 30 touches and two goals, with Lachie Whitfield also influential with 31 disposals.